Endo Agar
Also known as：Endo Agar Base · Endo Medium · Endo's Agar · Endo's Medium · Lactose Fuchsin Sulphite Agar · Fuchsin Sulfite Agar · Classical Endo Agar
For the isolation and differentiation of coliform organisms and other Gram-negative enteric bacilli from water, dairy products, and food.
- Category
- Dehydrated Culture Media
- Dissolve per litre
- 41.5 g
- Pack sizes
- 500 g · 5 kg · 25 kg
- Certifications
- ISO 22000 · Halal
Data updated：2026-11-06
Brand cross-reference：BD Difco Endo Agar · Oxoid Endo Agar Base · Merck Endo Agar Brand cross-reference
Overview
Endo Agar is an agar (solid) medium, a selective medium for food and clinical testing that suppresses competing flora and makes target colonies recognisable. Basic fuchsin differentiates lactose fermenters; used for coliform testing of water and food. STBIO manufactures it from food-grade raw materials in an ISO 22000 certified facility, with a COA for every batch. This is the Halal-certified version.
Principle
Endo Agar is based on the medium described by Endo for the differentiation of lactose-fermenting from non-fermenting enteric bacteria.¹ Peptone supplies nitrogen, amino acids, and peptides, lactose serves as the fermentable carbohydrate, and dipotassium hydrogen phosphate buffers the medium. Sodium sulphite and basic fuchsin inhibit Gram-positive organisms. In the prepared medium, sodium sulphite decolourises basic fuchsin, giving a pale pink background. Lactose-fermenting organisms produce acetaldehyde, which reacts with the sulphite and releases the fuchsin, so that the colonies turn red. Vigorous lactose fermenters such as Escherichia coli form red colonies with a characteristic green metallic sheen, caused by the crystallisation of fuchsin on the colony surface.² Non-lactose-fermenting organisms, including Salmonella and Shigella, form colourless to pale pink colonies.³
How selective media fit into the testing workflow
Pathogen testing normally runs in three stages: a pre-enrichment medium such as Buffered Peptone Water repairs injured cells and raises numbers, a selective enrichment then suppresses competing flora, and finally a selective differential agar isolates the target colonies. Selective agents are typically bile salts, dyes, or antibiotics; differential agents make target colonies develop a characteristic colour or morphology. Choose the combination specified by the method you follow.
Directions
Suspend 41.5 g of powder in 1 L of purified water. Heat with continuous stirring and bring to the boil for 1 minute. Sterilize by autoclaving at 121°C for 15 minutes. Cool to 45-50°C. Mix well and pour into sterile Petri plates, protecting the medium from light. Test the finished medium for performance using stable, standard control cultures.
Cultural response
| Test organism | ATCC | Growth |
|---|---|---|
| Escherichia coli | 25922 | good-luxuriant |
| Klebsiella aerogenes | 13048 | good-luxuriant |
| Salmonella enterica ser. Typhimurium | 14028 | good-luxuriant |
| Shigella flexneri | 12022 | good |
| Enterococcus faecalis | 29212 | inhibited |
Product highlights
- Food-grade raw materials, produced in an ISO 22000 certified facility
- Halal certified, suitable for the Malaysian, Indonesian, and Middle Eastern markets
- Manufactured to the standard formulation, 41.5 g per litre
- Performance verified against standard control strains before release (Escherichia coli, Klebsiella aerogenes, Salmonella enterica ser. Typhimurium, Shigella flexneri, Enterococcus faecalis)
- Available in 500 g / 5 kg / 25 kg, from laboratory to industrial scale
- COA, specification sheet, and technical data sheet available; samples on request
- Manufactured in Taiwan with reliable supply
Food grade versus laboratory grade
Most culture media suppliers use laboratory-grade raw materials, which are held to lower standards for heavy metal residues, microbial contamination control, and traceability. That is adequate for pure research but not for applications with stricter raw-material requirements. STBIO manufactures with food-grade raw materials throughout, in a facility certified to ISO 22000 food safety management.
- Food microbiology laboratories working to ISO 17025 or equivalent requirements
- Biotech manufacturers exporting fermentation products and needing full raw-material traceability
- Organisations with ESG or compliance audit requirements across their supply chain
- Companies sourcing both Halal and non-Halal products who need one consistent material grade
Frequently asked questions
01Can selective media be autoclaved?
Not always. Some media containing dyes or selective inhibitors lose their selectivity if overheated and should only be heated until fully dissolved, without autoclaving. Follow the preparation instructions for this product, and contact us if you are unsure.
02How much powder per litre?
Use 41.5 g per litre of deionised water; preparation and sterilisation conditions are given on the specification sheet.
03Which organisms is it suitable for?
Coliforms, Gram-negative, O157 E. coli O157:H7, Salmonella, Shigella, Escherichia coli, Klebsiella aerogenes, Salmonella enterica ser. Typhimurium, Shigella flexneri, Enterococcus faecalis. See the cultural response table and the specification sheet.
04What are the equivalent brand products and standard methods?
Cross-reference: BD Difco Endo Agar, Oxoid Endo Agar Base, Merck Endo Agar. Standard methods: . Formulations may differ slightly between makers; refer to the specification sheet.
05Can it be used for food-grade applications?
Yes. It is made from food-grade raw materials in an ISO 22000 certified facility and is suitable for culturing starters for fermented products that are consumed directly.
06How is this product prepared?
Suspend 41.5 g of powder in 1 L of purified water. Heat with continuous stirring and bring to the boil for 1 minute. Sterilize by autoclaving at 121°C for 15 minutes. Cool to 45-50°C. Mix well and pour into sterile Petri plates, protecting the medium from light. Test the finished medium for performance using stable, standard control cultures.
07Is there a non-Halal version?
Yes. This is the Halal certified version; an equivalent standard version is also available.
08How do I request a bulk quotation, and can you provide a COA?
Yes. This product is available in 500 g, 5 kg, 25 kg. Tell us your application and volume when requesting a quotation; we reply within one working day and can supply the COA, specification sheet, and technical data sheet.
Used in these applications
References
- 1. Endo S., 1904. Über ein Verfahren zum Nachweis der Typhusbacillen. Zentralbl. Bakteriol. Abt. I Orig., 35:109-110.
- 2. American Public Health Association, Standard Methods for the Examination of Water and Wastewater, current edition, APHA Press, Washington, D.C.
- 3. MacFaddin J. F., 1985. Media for Isolation-Cultivation-Identification-Maintenance of Medical Bacteria, Williams & Wilkins, Baltimore.